Environmental Control of Hypocotyl Elongation.

The hypocotyl is the embryonic stem connecting the primary root to the cotyledons. Hypocotyl length varies tremendously depending on the conditions. This developmental plasticity and the simplicity of the organ explain its success as a model for growth regulation. Light and temperature are prominent growth-controlling cues, using shared signaling elements. Mechanisms controlling hypocotyl elongation in etiolated seedlings reaching the light differ from those in photoautotrophic seedlings. However, many common growth regulators intervene in both situations. Multiple photoreceptors including phytochromes, which also respond to temperature, control the activity of several transcription factors, thereby eliciting rapid transcriptional reprogramming. Hypocotyl growth often depends on sensing in green tissues and interorgan communication comprising auxin. Hypocotyl auxin, in conjunction with other hormones, determines epidermal cell elongation. Plants facing cues with opposite effects on growth control hypocotyl elongation through intricate mechanisms. We discuss the status of the field and end by highlighting open questions. Expected final online publication date for the Annual Review of Plant Biology, Volume 75 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates

Heart rate control during treadmill exercise using input-sensitivity shaping for disturbance rejection of very-low-frequency heart rate variability

AbstractBackgroundAutomatic and accurate control of heart rate (HR) during treadmill exercise is important for prescription and implementation of training protocols. The principal design issue for feedback control of HR is to achieve disturbance rejection of very-low-frequency heart rate variability (VLF-HRV) with a level of control signal activity (treadmill speed) which is sufficiently smooth and acceptable to the runner. This work aimed to develop a new method for feedback control of heart rate during treadmill exercise based on shaping of the input sensitivity function, and to empirically evaluate quantitative performance outcomes in an experimental study.MethodsThirty healthy male subjects participated. 20 subjects were included in a preceding study to determine an approximate, average nominal model of heart rate dynamics, and 10 were not. The design method guarantees that the input sensitivity function gain monotonically decreases with frequency, is therefore devoid of peaking, and has a pre-specified value at a chosen critical frequency, thus avoiding unwanted amplification of HRV disturbances in the very-low-frequency band. Controllers were designed using the existing approximate nominal plant model which was not specific to any of the subjects tested.ResultsAccurate, stable and robust overall performance was observed for all 30 subjects, with a mean RMS tracking error of 2.96beats/min and a smooth, low-power control signal. There were no significant differences in tracking accuracy or control signal power between the 10 subjects who were not in the preceding identification study and a matched subgroup of subjects who were (respectively: mean RMSE 2.69 vs. 3.28beats/min, p=0.24; mean control signal power 15.62 vs. 16.31×10−4m2/s2, p=0.37). Substantial and significant reductions over time in RMS tracking error and average control signal power were observed.ConclusionsThe input-sensitivity-shaping method provides a direct way to address the principal design challenge for HR control, namely disturbance rejection in relation to VLF-HRV, and delivered robust and accurate tracking with a smooth, low-power control signal. Issues of parametric and structural plant uncertainty are secondary because a simple approximate plant model, not specific to any of the subjects tested, was sufficient to achieve accurate, stable and robust heart rate control performance

The impact of strategic climate legislation: evidence from expert interviews on the UK Climate Change Act

This paper assesses the importance of a strategic legal framework for action against climate change, using the UK Climate Change Act as an example. Passed in 2008, the Climate Change Act is one of the earliest and most prominent examples of framework legislation on climate change. It contains several innovative features that have since been replicated in other framework laws. We use stakeholder interviews to assess the strengths of the Act and whether it has succeeded in creating an integrated, informed and forward-looking policy process. Respondents felt that the Act had established a firm long-term framework with a clear direction of travel. However, they differed on whether the Act provided sufficient policy certainty and protection against political backsliding. Most respondents felt that the Act had changed the institutional context and the processes through which climate change is addressed. As a result, interviewees believe that the Act has helped UK climate policy to become better informed, more forward looking and better guided by statutory routines

Confirmatory Factor Analysis of the French Version of the Savoring Beliefs Inventory.

The Savoring Beliefs Inventory (SBI) is a measure designed to assess attitudes toward savoring positive experience within three temporal orientations: the past (reminiscence), the present moment (present enjoyment), and the future (anticipation). The aim of this study was to validate the structure of the SBI-French version. The scale was tested with 335 French-speaking participants. Two models were estimated: a one-factor model representing a general construct of savoring and a three-factor model differentiating between anticipation, present enjoyment, and reminiscence. Several indicators of model fit were used: the root mean square error of approximation (RMSEA), the comparison fit index (CFI), the Tucker-Lewis fit index (TLI), and the standardized root mean residual (SRMR). A chi-square difference test was used to compare the two models. The model fit of the three-factor model assessed by the SRMR showed to be excellent, while it could be considered as satisfactory according to the CFI and TLI coefficients. RMSEA, however, was slightly less adequate. The model fit for the one-factor model seemed less adequate than the three-factor solution. Further, the chi-square difference test revealed that the three-factor model had significantly better fit than the one-factor model. Finally, the reliability of the four scores (anticipating pleasure, present moment pleasure, reminiscing pleasure, and total score) was very good. These results show that the French version of the SBI is a valid and valuable scale to measure attitudes regarding the ability to savor positive experience, whether it be in anticipation, reminiscence, or the present moment

Donor characteristics and the allocation of aid to climate mitigation finance

We make use of a panel dataset of 22 donor countries from 1998 to 2009 to examine the links between donor characteristics and the share of overseas development assistance allocated to climate mitigation finance. We find that donors with a larger green domestic budget tend to allocate a smaller portion of overseas aid to mitigation finance (possibly as a result of a competing interest between spending on domestic environmental projects and international climate projects). The opposite holds for donor countries with better institutions (governance) that have ratified the Kyoto Protocol. We also find important discrepancies when comparing the effects of donor characteristics on committed versus disbursed mitigation finance (as a share of aid). For the latter, only commitment to the Kyoto Protocol appears to be of high statistical significance

p53 suppresses type II endometrial carcinomas in mice and governs endometrial tumour aggressiveness in humans

Type II endometrial carcinomas are a highly aggressive group of tumour subtypes that are frequently associated with inactivation of the TP53 tumour suppressor gene. We show that mice with endometrium-specific deletion of Trp53 initially exhibited histological changes that are identical to known precursor lesions of type II endometrial carcinomas in humans and later developed carcinomas representing all type II subtypes. The mTORC1 signalling pathway was frequently activated in these precursor lesions and tumours, suggesting a genetic cooperation between this pathway and Trp53 deficiency in tumour initiation. Consistent with this idea, analyses of 521 human endometrial carcinomas identified frequent mTORC1 pathway activation in type I as well as type II endometrial carcinoma subtypes. mTORC1 pathway activation and p53 expression or mutation status each independently predicted poor patient survival. We suggest that molecular alterations in p53 and the mTORC1 pathway play different roles in the initiation of the different endometrial cancer subtypes, but that combined p53 inactivation and mTORC1 pathway activation are unifying pathogenic features among histologically diverse subtypes of late stage aggressive endometrial tumours